Exemplary embodiments in accordance with principles of inventive concepts relate to a pixel, or pixel sensor, included in a depth sensor (also referred to herein as a distance sensor) and an image processing system including the same, and more particularly, to a pixel included in a distance sensor for providing high sensitivity and demodulation contrast and an image processing system including the same.
Image sensors include a plurality of pixels, also referred to herein as pixel sensors, that convert photons within a spectrum band into electrons. Image sensors are widely employed in portable electronic devices, such as cellular telephones or, or, more particularly, smart phones, and improvements in such sensors would benefit a large number of users.
Information about the distance (also referred to herein as depth) between an object and an image sensor, as well as about the color of an imaged object is necessary to obtain a three-dimensional (3D) image. Methods for obtaining information about the distance between the object and the image sensor may be active or passive.
Time-of-flight (TOF) and a triangulation methods are representative active methods. In the TOF method, modulated light is emitted to the object, light reflected from the object is sensed, and the distance is calculated from a phase change in the reflected light. In the triangulation method, the position of light emitted by a laser or the like a certain distance from the sensor and the position of reflected light are sensed and the distance between the sensor and the object is calculated using triangulation. In passive methods, the distance is calculated using only image information, without emitting light. A stereo camera representatively uses a passive method.